2013 APPS - KL. The Importance of Charge Testing in Delivering Well Performance

Transcription

1 - KL The Importance of Charge Testing in Delivering Well Performance APPS Presented by Mark S Brinsden Shell Chair API SC19B

2 1. Contents 1. Contents 2. Review of API testing for charge performance 3. Using API testing 4. Selecting Charges and Guns for well performance 5. Modelling for Performance 6. Conclusions and Way Forward

3 2. Review of API testing for charge performance API RP19B is currently being rewritten to bring it up to date. One of the key drivers, is about making it clear that you need to use the right kind of testing to really understand how your gun and charge are going to behave in your reservoir.

4 2. Review of API testing for charge performance Section 1: Evaluation under surface conditions in concrete targets Provides a fit-for-purpose method of identifying variability in charge data (LP & EHD) charge interference verified QC test but also used as benchmark for charge penetration. Although designed to be consistent and arguably an improvement on API RP 43 Section 1 target is know to be inconsistent and unsuitable reference for reservoir penetration benchmark. A new data sheet has been drafted including disclaimer... Penetration Data recorded in API RP19B Section 1 may not directly correlate to penetration downhole.

5 2. Review of API testing for charge performance Section 2: Evaluation under stress conditions in rock targets Basic test to measure stressed rock penetration profile and performance. Can be expanded to different rocks, diameters and stress conditions. Could also be used as one of the standards for improved charge performance testing using a selection of outcrop rock or synthetic rock targets.

6 2. Review of API testing for charge performance Section 4: Evaluation of flow performance under simulated downhole conditions Suitable for evaluating flow, penetration and dynamic perforating event under simulated wellbore and reservoir conditions. Section 4 has been rewritten due to need to improve the correlation in performance between the different test cells in the market and has been submitted to vote, has passed for issuing.

7 2. Review of API testing for charge performance Section 3: Temperature Performance Section 5: Debris Evaluation Section 6: Gun Swell (New) All three of these also have a great deal of relevance in understanding how well charges and guns perform under reservoir conditions.

8 3. Using API testing Charge consistency

9 3. Using API testing API RP43 4 th edition Section 2 Berea penetration (in.) in. concrete 8 in. or 12.5 in. Berea? 10 in. Berea 10.5 in. or 18 in. concrete? API RP43 4 th edition Section 1 concrete penetration (in.) Unstressed Section 1 concrete data provides no strong correllation to stressed rock penetration or in-situ reservoir rock penetration this has been known for years.

10 3. Using API testing 50 Penetration in Stressed rock API Concrete penetration Same gun & DP charge size Required test points? - Defines slope and intercept Modified representative data not actual numbers Rock Strength Indicator due to Confinement and Pore Pressure psi.

11 3. Using API testing So we understand from this that :- 1. There is no general correllation between surface concrete penetration and down hole 2. We need to select charges for specific reservoir type 3. Relying on concrete penetration is only suitable for very simple operations 4. A charge can be great for certain reservoir conditions but relatively less useful for others

12 4. Selecting Charges and Guns for well performance What are the kind of things we need to think about when selecting a gun and charge for a reservoir :- 1. How is gun to casing clearance going to effect performance. Testing the charge under simulated downhole conditions gives us actual penetration and casing hole diameter. Actual Example:- 2-7/8in Premium Gun penetrating 9-5/8in casing into 6000psi UCS Stressed Target Gun Clearance Target Penetration Casing Entrance Hole

13 4. Selecting Charges and Guns for well performance What are the kind of things we need to think about when selecting a gun and charge for a reservoir :- 2. How is penetrating double casing going to effect performance. Actual Example:- 2-7/8in Premium Gun penetrating 5-1/2in casing cemented in 9-5/8in casing into 6000psi UCS Stressed Target Gun Clearance Target Penetration Casing 1 Entrance Hole Casing 2 Entrance Hole NA

14 4. Selecting Charges and Guns for well performance What are the kind of things we need to think about when selecting a gun and charge for a reservoir :- 3. Is there poor Vert. Perm., is the reservoir interbedded with impermeable Layers. Look at relative performance of higher shot density guns lower penetration, but access every layer. 4. Reservoir temperature is the gun suitable for your operating temperature, can you safely use an HNS charge at borderline temperatures. Use temp charts but what about the change in charge performance with temperature use section Is gun debris an issue and if so is the data in Sect 5 suitable for you to work out if a gun is suitable? 6. Will the gun operate in your downhole conditions, is gas flowing past your gun, is the gun capable of being shot in gas. Will the gun swell be an issue we want the largest gun probably for clearance and penetration but will it come out Sect 6.

15 5. Modelling for Performance How important is modelling for performance given that we can t test every downhole condition in the lab? Difference between an optimistic model and model based on stressed rock data 290 BPD similar to reservoir. 220 BPD 21in Av. Penetration Example: 2-7/8in Premium Gun in 7in casing, 14in Av. Penetration No Gun Clearance. 12 in Mud filtrate invasion.

16 5. Modelling for Performance Most current models rely on Sect 1 penetration and apply a correlation for rock strength, stress (in some models), casing, cement and gun clearance. SPOT has 2 correlations and can use Sect 2/4 testing (as used in previous example), but still relies on converting the results back into Sect 1 penetration before predicting modelled penetration, good but not charge specific enough. Schlumberger have a model and correlation based on a large number of stressed rock shots. With well documented and charge specific correlations. This type of model is being considered by other contractors. But all premium charges will need to be shot under various rock strength and stress conditions to make this work.

17 5. Modelling for Performance Ref EWAPS Detailed review of hundreds of shots under stressed conditions into different rock types with different charges. It is suggested that each charge can be characterised by a combination of factors which identify a relative slope/curve and height for penetration. In addition each rock, pore pressure and confinement condition, can also be characterised by a single term the Ballistic Indicator Function. So going back to my earlier slide showing the performance of 3 similar charges :-

18 5. Modelling for Performance How a charge performs is described by a curve with a slope and relative height. This allows for some charges to clearly perform better in certain rock strengths and stress regimes. Assisting in charge selection. 30 Penetration Reservoir rock conditions characterised for UCS, overburden, pore press and porosity by Ballistic Indicator Function

19 6. Conclusions and Way Forward Is penetration consistency in outcrop rock is an issue? Are we shooting the target material in the right plane perpendicular or parallel to bedding? We are still getting significant variations in charge performance, is this due to target or charge consistency? Should we continue to look at synthetic target development? Should we look at a consistent way of modelling charge performance in stressed rock if so what model? Some possible ways forward

20 6. Conclusions and Way Forward Some possible ways forward Is penetration consistency in outcrop rock is an issue? Even though Berea is now more consistent we still have significant variation. Are we shooting the target material in the right plane perpendicular or parallel to bedding? Consistency is the main thing, shooting perpendicular to bedding does appear to create greater consistency. We are still getting significant variations in charge performance, is this due to target or charge consistency? Some recent tests on commodity charges have shown some significant loading inconsistency. Should we continue to look at synthetic target development? Ideally, a joint industry effort is worth the effort for price and consistency. Should we look at a consistent way of modelling charge performance in stressed rock if so what model? Ideally we need an industry agreed and tested model that can be used in all penetration models.

21 - KL The Importance of Charge Testing in Delivering Well Performance APPS Thank You Presented by Mark S Brinsden Shell Chair API SC19B